campbell



1. c` CAMPBELL.

VACUUM PNEUMATlC HAMMER.

APFLICAIION YILD jUl l5. ISIS.

Patented June 8, 1920.

3 SHEETS-SHEET l.

1. C. CAMPBELL.

VACUUM PNEUMAUC HAMMER.

AFPLICATIN FILI!! JUl l5. |9l6.

o James C. Cmpbdgwemor 4 Atty;

l. C. CAMPBELL. VACUUM PNEUMATC HAMMER. :hule/umu mtu wu 15.1915.

Patented June 8, 1920.

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.j/me; ,''mpggll Inventum" by Ank Vns

- the line 4 4 in .from the rear toward the front of the tool.' .Slidably arranged within the casing 10 and JAMES (3. CAMPBELL. 0F NEW YQRli, N. Y.

VACUUM PNEUMATIC HAMMER.

Specification of Letters Patent.

Patented June H. 11h20.

Application tiled July 15, 1916. Serial No: 109,455

and useful Improvements in Vacuum Pneu-v matic Hammers, of which the Vfollowirn.; is a specification.

This invention relates to vacuo-pneumatic power hammers and its novelty consists inthe construction and adaptation of the nirts as will be more fully4 hereinafter pointe out. The purpose of the invention is to pro.- duce a power hammer of simple construction, not likely to get out of order and of ra id and eflicient operation.

n the drawin there is illustrated a preferr-ed form of iisammer'embod. ing my invention. Figure 1 is a central ongitu'dinal section of the device with the parts shown in the positions they assume when at rest; Fig. 2 is a section on the plane ofthe line 2-2 in Fi 1 showing the piston hammer retracted; Fig. 3 is a section similar to F ig. 2 showing the iston hammer in a forward position and with some of the parts in ele` vation; Fig. 4 is a section on the plane of Figr, showing the piston hammer retracted; Fig. 5 is a transverse section o n the plane of the line 5--5 in Fig. 4; Fig. 6 is a view similar to Fig. 1, showing'the pistonhammer in ari intermediate position; and Fig. 7 is a miniature view of the entire ldevice. -Fig 8 is a detail sectional view on the line 8 8 of Fig. 4. Fig. 9 is a detail sectional View von the line 9--9 of Fn the drawings, 10 is a casing preferably of cylindrical form, and secured to it in any suitable manner is a eecondcasing indicated at 11. The casing 10 is slightly restricted at 12 to form a shoulder against which there is adapted to rest an enlarged annulus 13 of a sleeve 14 which is securedv firmly within the casing 10 and` is generally cylindrical in form but is longitudinally truncated at sev eral places as indicated at 15 (see Fig. 5) whereby there are clearances between the inner surface of the casing and the outer surfface of the sleeve forming air passageways. V'Izheredare a series of ports, indicated at 16, .1, an

L8, arrangedet intervals along the sleeve and they gradually increase in width sleeveA 14 4is a cylinder, 20, conslderably longer than the sleeve, to the forward end of whichhv threads 21 or iu anyY other lsuitable manner is secilred :l tool holder 22 und which is provided with a central hoi-c adapted to receive the shank of a tool indicated at 23. The cylinder is provided at intervals with a series of ports, indicated at 26, 2 and 28, all of the saule size, and cirularly arranged and adapted .to register with the ports 16, 1 7 and 18'of thc sleeve 14. 'lightly fitting within the cylinder :ffl there is arranged to reciprocate piston hammer 3U. coiled spring 3l is inserted within the casing 10 between the holder 22 and sleeve 14. The casing l0 is provided with a guide finger 32 with which the tool holder'f22 is in slidahlc contact.

The 'second casing 1l constitutes part of a compressor and is of rounded form and contains the uil' controllim r or compressing device in the form of an eccentricully set revolving roll mounted to rotate in suitable bearings formed in the casing and actuated from a source of power not shown. It is provided with a cam groove 86 and with u transverse vane 3'( which slides radially with respect to its center and is provided with suitable packing at each edge and coiltacts with the interior of the casing. B v the rotation of this vane the air within the cas ing is alternately compressed and allowed to expand und the device forms in effect a rota r v air pump althouoh it lioth compresses and exhausts the air. t the side ofthe casing 1l, there are provided ports indicated at 4U und 4l. which communicate with u space 4:5 immediatel \Y hach of the sleeve 14, which in turn communicates with the spaces 15, l5. the port 4U licing an inlet port and the port 4l an outlet port when the vane 37 rotates clockwise.

A slide valve indicated at 43 is .-irrnnged in the forward end of thc casingI ll, and iS adapted to he reciproratcd laterally therein hy means of a tin 44 secured thereto and y which engages the cam groove 36 in the roll 35.' By such I'ecipromition this vulve alternately closes and opens the inlet port 4t) and outlet' port 41. The slide valve controls' communication between the ports 4U and 4l respectively and other ports 40* and 41 which communicate with theinterior of the piston casing 11. i

A suitable handle indicated at 45 and attached to the easing 11 enablesfthe operator to hold the tool against the work. When the pai-ls of the tool are at rest, they are in the position shown in Fig. 1, and even ulthough the roll il." and vane 3T be revolving within the casin r and the slide valve i3 be aci uated and the aiv within the casing 11 be alternately compressed and exliiuted and driven through the inlet port -l0`into the passata-rays l5 within thel casing 1U, and exhausted t'voin such passageways, nevertheless there would be no movement of the piston hammer 3U because the ports of the .sleeve I4 would not register with the ports of the cylinder :ffl and no air would be adniitted to or could escape from such c yf inder. A

lf, however, the operator, pressing upon the handle 45, presses the tool 23 against the work and by so doing. moves the tool holder with respect to the casing 1U into the position shown in Fig. 2, thus compressing the spring 3l, hc will have caused the ports 16, 1T and 1S of the sleeve ll to register with the ports 26, ZTand 225 of the cylinder 20. liy this action, the air in compressed form is admitted to such ports and exhausts through such ports as the vane rotates. This variation of the density of the air in the space behind the piston hammer 30 causes the latter to vibrate or to be reciprocated rapidly within the cylinder and to strike repeated blows against the tool shank and consequent-ly upon the tool.

When the tool bolder is pressed back so that its rear end contacts with the front end of the casing 1l. then, as all of the ports in the'sleeve 14 register withall of the ports in the cylinder 20, there is the fulleststroke given to the piston hammer. If, however, the tool holder is only partly pressed back toward the casingr l0 as illustrated in Fig. G. the ports of the sleeve 14 will only register with a part of the ports i-n the cylinder 2U. and will thus permit a smaller quantity of air to be delivered to and exhausted from the interior of the cylinder, thus imparting an impulse of less energy to the piston ham incr. lt should be noted that the space within the c vlinder QH is practicallyair-tight, and that the actuation of the vane 37 hasthe effect practically of merely rapidly varying the density of the aii` within this cylinder. For this reason, the cylinder is not lili'ely to become hot and the. device can be operated .with comfort and without the provision ofA 'ni-ans for cooling it. I claim i l. ln a device of the character described, the combination with a cylinder member and a piston therein, of means for operating the latter, comprising a compressor havin a rotary piston, passageiazvs for delivering Huid between the compressor and cylinder member. an automatic controlling valve for tbc passageways, and a mechanical connection between the controlling valve and the rotary iiston of the compressor to actuate said va ve.

2. In a device of the character described, the combination with a cylinder member and a piston therein, of means for operating the latter, comprising compressing and exhausting mechanism including a `cylinder' and a rotary piston in the cylinder having a cam element, passageways between the com pi'essor and cylinder member, and a reciprocatory valve controlling the passageways and o )erated by the cam element.

Il. n a device of the character set forth thenombination with a cylinder member and a piston therein, of means for operating the latter, compsing a compressor having a rotary piston, a cam rotating with the piston, a, fluid delivery passageway between the crmpressor and cylinder member, a suction passageway between the compressor and cylinder member, an automatic valve controlling the passa eways, and means enraged and operated y the cam for actuating the valve.

4. In a device of the character set forth, the combination with a casing, of a cylinder located therein, a piston operating in the cylinder, a sleeve inter osed between the cylinder and casing an having a portion spaced from the latter and provided with ports, said cylinder having ports that register with the ports of sind portion of the sleeve, and means for supplying motive Huid to the space between tie cylinder and sleeve. 100

5. In a device of the character set forth, the combination with a casing, of a cylinder slidably located therein, a. piston operating in the cylinder, a sleeve inter osed'between the cylinder and casing and aving a portion spaced from the latter' and provided with ports, said cylinder having ports that move into and ont of register with the of said portion of the sleeve on the sliding movement of the cylinder, and a s ring' interposed between the sleeve and cyligndeiifnr resisting the movement of the lattl in die direction. v

6. In adevice of the character described, the combination with a casing, of an inter` nal cylinder slidable in the casing'and having ports, a sleeve interposed between the casing and internal cylinder 'andhaving a portion spaced from' the casing and provided with ports with which the ports o the internal` cylinder move 4i'ntio Yand out of register, a piston operating in the internal cylinder. and means for e'ecting the movement of said internal cylinderfa 7. In a device of the character described, the combination with an outer casing, of a tool holder slidable thereon and having an internal cylinder vlocated within the casing and slidable therein, said cylinder having lateral ports, and a sleeve interposed between the casing endinternalnylinder and haring a ortionspaced from'the former and pro vi ed with ports with which the ports of the c linder move into and out of register.

.8.' n device 'of the' charecter descrbed.

Stndinally o'ffthe casing.

' the casi 9. In a device of the cliarcter described,A

the combination with an outery casing, of a. tool holder eldelzvly mounted on one end of the same, an internal cylinder fixed to the tool holder and slidably mounted within the casing', said cylinder having sets oi laterally' disposed ports a sleeve interposed between an cylinder and. having ports with wliic i the ports'of the cylinder snceessivelyaline n on the sliding movements of the latter,` a' iston operating in the internal cflinder, an a. sprl l'.

f terposed between e sleeve end the too -V holder. l

In testimony whereof I ellix my signature.

JAMES c. CAMPBELL. 

